Patent documents 1 and 2 give examples of a plasma processing apparatus to which a conventional point-cusped magnetic field (PCM) is applied. The apparatuses disclosed in these patent literatures can generate plasma at a high density in the vicinity of a target attached to an electrode by forming a point-cusped magnetic field on the target. To generate a point-cusped magnetic field, a plurality of point-like magnets are arrayed on the back surface of the target such that all adjacent magnets have an equal distance between them and have magnetic pole end faces with opposite polarities.
In particular the plasma processing apparatus shown in patent document 1 rotates a magnet mechanism, which includes a plurality of magnets that form a point-cusped magnetic field, to rotate the point-cusped magnetic field on a sputtering target, thereby uniforming a circumferentially formed magnetic field.